Jerusalem: Prime Minister Benjamin Netanyahu warned Thursday that Israeli security would be at risk if the centre-left opposition won next week`s election, vowing he would not join a national unity government.

Netanyahu`s remarks are part of his media blitz just five days before the March 17 vote, with the latest polls showing his rightwing Likud lagging behind the rival centrist-left Zionist Union by at least three points.

"Our security is at great risk because there is a real danger that we could lose this election," he told the Jerusalem Post.

"If the gap between the Likud and Labour continues to grow, a week from now (Zionist Union leaders Isaac) Herzog and (Tzipi) Livni will become the prime ministers of Israel in rotation, with the backing of the Arab parties," he said.

"That will cause such a monumental shift in policy that it is a danger, and anyone who wants to stop it has to vote Likud to narrow the gap."

Should they form the next government they have agreed on a two-year rotation for the premiership, with Herzog taking the first tenure.

"You will get prime ministers who completely prostrate themselves to any pressure," Netanyahu said.

An amalgamation of seven opinion polls published Thursday evening by Project 61 pollsters predicted the Zionist Union would win 24 of the 120 seats in parliament against 20 for Likud.

The Joint List, a newly formed alliance of Israel`s main Arab parties, was seen coming third with 14 seats.

Under Israel`s electoral system, the government is formed not by the single largest party, but by whomever can build a coalition commanding a parliamentary majority.While the Zionist Union could emerge the largest party, Herzog would have a near-impossible task of forming a coalition, which would be comprised of small parties with contrasting agendas.

Besides Netanyahu forming a rightwing coalition with ultra-Orthodox parties, there is also the possibility of a national unity government, which would include a rotation between the heads of the Zionist Union and Likud.

But Netanyahu shot down that possibility in an interview with Channel 2 television.

"I will not be a prime minister in rotation, and that should be prevented," he said of a national unity government.

Netanyahu also lashed out against foreign-funded elements seeking to unseat him, to force Israel into making concessions against its good.

"There are vasts amounts of funds flowing from abroad, millions of dollars," he told Channel 2, claiming that "European states and leftwing people from outside" Israel were funding non-governmental organisations that encourage Arabs and leftwing Israelis to vote.

According to Netanyahu, this was "because they understand that if Tzipi and Bougie reach (the premiership), they`ll give everything up, and withdraw to the 1967 borders and divide Jerusalem," he said, using Herzog`s nickname.

Netanyahu recently said that making territorial concessions to the Palestinians would endanger Israel, without explicitly reneging on his 2009 speech that acknowledged the need for a Palestinian state.

Herzog, meanwhile told Channel 1 television that he "does not rule out parties or persons."

He also accused Netanyahu of "severe panic" in the closing days of his campaigning, in an interview with army radio.

"He`s returning to the rhetoric of cowardice and threats," he said. "The public wants change."

The Labour leader also received a boost in the form of endorsement from former president Shimon Peres, himself an ex-premier and Labour head.

"I have known Herzog and his family for many years, I`ve seen his excellent performances in senior positions and taking part in discussions and decisions crucial to Israel`s future," Peres said in a statement.

Peres, who stepped down as president in July, is a long-time critic of Netanyahu and his policies. In 1996, Netanyahu beat Peres in a premiership race.